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Abstract:

The invention relates to a method of optimizing a process for handling
mail, which method comprises the following steps: subjecting mailpieces
to a first machine-sorting cycle in which a plurality of first sorting
outlets are allocated to respective ones of a plurality of first delivery
destinations having high rates of filling and one other sorting outlet is
allocated to second delivery destinations having low rates of filling;
directing separators to the first sorting outlets; re-circulating the
mailpieces coming from the other sorting outlet; and subjecting them to a
second sorting cycle in which the first sorting outlets are allocated to
the second delivery destinations. If the sorting outlets use storage
bins, at the end of the second sorting cycle, the mailpieces of a first
destination and the mailpieces of a second destination are sorted in
layers in the same bin by being separated by a separator.

Claims:

1. A method of optimizing a process for handling mail in a sorting
machine, said method comprising the following steps: subjecting
mailpieces to a first machine-sorting cycle in which a plurality of first
sorting outlets of the sorting machine are allocated to respective ones
of a plurality of first delivery destinations and at least one other
sorting outlet of the sorting machine is allocated to a plurality of
second delivery destinations; directing separators for physically
separating mailpieces through the sorting machine to respective ones of
the first sorting outlets; re-circulating to the inlet of the sorting
machine the mailpieces coming from said other sorting outlet; and
subjecting them to a second sorting cycle in which the plurality of first
sorting outlets are allocated to respective ones of the plurality of
second delivery destinations.

2. A method according to claim 1, wherein mailpieces are collected and
sorted in a first mail handling center so as to be transported in storage
bins to M second mail handling centers in communication with the first
mail handling center, the sorting of the mail in the first center
comprising separating the mailpieces in a sorting machine having N
sorting outlets, each of which uses at least one storage bin so as to
form M groups of storage bins in which the mailpieces are stored, these M
groups of storage bins being for respective ones of said M second mail
handling centers, and wherein the sorting machine is controlled by one or
more sorting cycles so as to segment each group of storage bins for a
second mail handling center in such a manner as to distinguish between
the mailpieces stored in said bins depending on a plurality of delivery
destinations associated with said second mail handling center, said
method further comprising the following steps: a) preparing the sorting
machine for a first sorting cycle for sorting the mailpieces, the sorting
outlets of the sorting machine comprising a plurality of first sorting
outlets and at least one second sorting outlet distinct from said first
sorting outlets, the preparation consisting in: a.1 allocating P first
sorting outlets to respective ones of P first delivery destinations
associated with a second mail handling center in question, and doing so
for each second mail handling center with the condition M×P less
than N, where P is greater than 1, the P first sorting outlets allocated
to a second center being distinct from the P first sorting outlets
allocated to another second mail handling center; and in a.2 allocating
said second sorting center to M×P second delivery destinations
associated with respective ones of M second mail handling centers; b)
subjecting the mailpieces to the first sorting cycle in the sorting
machine so as to collect, in at least one storage bin at each first
sorting outlet, mailpieces corresponding to a first delivery destination
associated with a second mail handling center and, at the second sorting
outlet, mailpieces corresponding to the M×P second delivery
destinations; c) inputting into the sorting machine M×P separators
so as to place them in respective ones of the M×P storage bins
being filled at respective ones of said first sorting outlets; d)
preparing the sorting machine for a second sorting cycle for sorting the
mailpieces, the preparation consisting in: d.1 allocating the M×P
first sorting outlets of the sorting machine to respective ones of the
M×P second delivery destinations associated with the M second mail
handling centers; and in d.2 re-circulating into the inlet of the sorting
machine the mailpieces received in the second sorting outlet during the
first sorting cycle; and e) subjecting said re-circulated mailpieces to
the second sorting cycle in the sorting machine so as to collect, in each
storage bin being filled at each first sorting outlet, mailpieces
corresponding to a second delivery destination, these mailpieces that
correspond to a second delivery destination being separated from the
mailpieces that correspond to a first delivery destination by a separator
in said storage bin.

3. A method according to claim 2, wherein said sorting outlets include a
third sorting outlet that is distinct from said first and second sorting
outlets; wherein, in step a.2), the preparation further comprises
allocating the third sorting outlet to M×P third delivery
destinations associated with respective ones of the M second mail
handling centers; and wherein, in step b), the mailpieces are subjected
to the first sorting cycle so as to collect, at said third sorting
outlet, the mailpieces corresponding to the M×P third delivery
destinations; the method further comprising the following steps,
subsequent to step e): f) inputting into the sorting machine M×P
other separators so as to place them in respective ones of the M×P
storage bins being filled at respective ones of the said first sorting
outlets; g) preparing the sorting machine for a third sorting cycle for
sorting the mailpieces, the preparation consisting in: g.1 allocating the
M×P first sorting outlets of the sorting machine to respective ones
of the M×P third delivery destinations associated with the M second
mail handling centers; and in g.2 re-circulating into the inlet of the
sorting machine the mailpieces received in the third sorting outlet
during the first sorting cycle; and e) subjecting said re-circulated
mailpieces to the third sorting cycle in the sorting machine so as to
collect, in each storage bin being filled at each first sorting outlet,
mailpieces corresponding to a third delivery destination, these
mailpieces that correspond to a third delivery destination being
separated from the mailpieces that correspond to a second delivery
destination by a separator in said storage bin.

4. A method according to claim 2, wherein the magnitude P is determined
on the basis of the ratio N/M.

Description:

TECHNICAL FIELD

[0001] The invention relates to the field of postal sorting, and more
particularly to the field of sorting mail automatically, whereby
mailpieces are collected and sorted in a first mail handling center and
are then transported in storage bins to second mail handling centers in
communication with the first mail handling center, and whereby the mail
sorting in the first center consists in separating the mailpieces in a
sorting machine having a plurality of sorting outlets, each of which uses
at least one storage bin so as to form a certain number of groups of
storage bins in which the mailpieces are stored, the groups of storage
bins being for respective ones of said second mail handling centers, and
whereby the sorting machine is controlled by one or more sorting cycles
so as to segment each group of storage bins that are for a second mail
handling center in such a manner as to distinguish between the mailpieces
stored in said bins depending on a plurality of delivery destinations
associated with said second mail handling center.

PRIOR ART

[0002] The invention relates more particularly to a method of optimizing
the filling of the bins in such a process for handling mail, in
particular when the mailpieces are collected and sorted in an "outward"
sorting center at which "outward" sorting or "routing" sorting is
performed and from which they are transported, in particular by air,
road, or rail, in storage bins, to "inward" sorting centers at which
"inward" sorting or "delivery" sorting is performed. In an inward sorting
center, the mailpieces thus arrive in storage bins that are already
pre-sorted by delivery destination, thereby making it possible to reduce
the time necessary for performing the sorting process in the inward
sorting center. Thus, outward sorting in the outward sorting center makes
it possible to achieve pre-sorting, while inward sorting in the inward
sorting center makes it possible to prepare the delivery round or
"postman's walk".

[0003] Conventionally, a sorting machine receives as input a flow of
mailpieces disposed in random order, and delivers as output an ordered
flow of mailpieces, i.e. a flow of mailpieces disposed in a predetermined
order. In outward sorting, the predetermined order substantially
corresponds to separation by groups of delivery addresses. In inward
sorting that is performed downstream from the outward sorting, the
predetermined order thus corresponds to sequential delivery of the
mailpieces by one or more mail carriers.

[0004] A plurality of inward sorting centers that are in mutual
communication constitute a postal sorting cluster that can be distributed
over a geographical zone that may be small or large, e.g. a national
zone. In such a postal sorting cluster, each inward sorting center also
constitutes an outward sorting center relative to the other inward
sorting centers of the cluster.

[0005] In general, the sorting machines that are used in a postal sorting
cluster for outward sorting purposes are equipped with a small number of
sorting outlets due to cost and compactness constraints. Typically, such
a sorting machine has about one hundred sorting outlets using removable
storage bins in which the mailpieces are stored flat, for example. Each
such storage bin has a storage capacity of about 50 mailpieces. Sorting
the mailpieces in such a sorting machine may require a plurality of
sorting passes and the volume of the mail to be handled may require
several tens of storage bins per sorting outlet.

[0006] An outward sorting machine thus normally comprises: an unstacker
magazine receiving a batch of mailpieces to be sorted such as
large-format magazines or letters with or without paper or plastics
wrappers or envelopes; a certain number of sorting outlets that are
respectively fed with empty removable bins for storing the sorted
mailpieces; and a sorting conveyor interposed between the unstacker
magazine and the sorting outlets, and controlled by an electronic
processor unit for directing each mailpiece to be sorted towards a
respective sorting outlet on the basis of an identifier making it
possible to determine the delivery destination code that is normally
printed on the mailpiece, and on the basis of an allocation table stored
in a memory in the electronic processor unit and correlating the code to
a given sorting outlet of the machine.

[0007] In a conventional outward sorting process, groups of storage bins
are constituted that comprise a large number of partially full bins since
segmenting the bins into a group of bins for an inward sorting center
generally takes place by changing bins in the sorting outlet in question
of the machine. If it is assumed that several tens of delivery
destinations can be associated with an inward sorting center, it is
possible, at the end of the outward sorting process for each inward
sorting center to have several tens of partially full storage bins. Such
partially full storage bins take up space unnecessarily in the means for
transporting the mail, thereby resulting in additional costs for
operating the postal sorting cluster.

[0008] Over a plurality of sorting cycles in the machine, some mailpieces
may be taken from the sorting outlets and placed at the inlet of the
machine, and this may happen in repeated manner. In certain situations,
the relationship between the maximum number of delivery destinations that
a sorting machine can manage in a given sorting process, the number of
sorting outlets available for the sorting process, and the number of
sorting cycles in the sorting process can lead to inefficient use of the
sorting machine. More particularly, such situations can arise when the
number of delivery destinations to cover is hardly any greater than the
maximum number of delivery destinations that can really be managed by the
machine for a certain number of sorting cycles, and is considerably
smaller than the maximum number of delivery destinations that can be
managed with the sorting process using the next highest number of sorting
cycles. Situations of that type can be managed either by increasing the
number of sorting cycles, or by increasing the number of sorting outlets,
or indeed by subdividing the batch of mailpieces into two or more subsets
to be processed separately.

[0009] But those three solutions are unsatisfactory for various reasons.
Increasing the number of sorting cycles in a sorting process is
detrimental to good use of the machine and increases the time and the
costs of the sorting process. Increasing the number of sorting outlets of
the machine can also give rise to additional costs for manufacturing the
machine and to a larger amount of space being necessary for storing it.
In addition, that solution is not necessarily possible for sorting
machines that have already been manufactured or installed. Finally,
subdividing the batch of mailpieces into subsets can be incompatible with
the needs of the end customer and, in any event, requires redefinition of
all of the machine parameterization of the sorting process, which gives
rise to additional costs and time.

[0010] Situations can also arise in which the number of delivery
destinations to be managed is comparable to the maximum number of
delivery destinations addressable in the sorting process for a given
number of sorting cycles, but certain delivery destinations have a rate
of filling that is so high that they can hinder use of sorting outlets
during the various sorting cycles, thereby inevitably generating
inefficient use of the machine.

SUMMARY OF THE INVENTION

[0011] An object of the invention is thus to propose a method of
optimizing a mail handling process as indicated above by minimizing the
number of bins to be transported from one postal sorting center to
another postal sorting center while keeping the same level of separation
of the mailpieces.

[0012] Another object of the invention is to propose such a method that
aims to reduce the proportion of partially full bins at the end of
outward sorting, in particular, without however being detrimental to
efficient use of the sorting machines.

[0013] The invention stems from the observation that, in a sorting
process, most (about 80%) of the mail is distributed over a few main
delivery destinations (about 20% of the delivery destinations), the
remainder of the mail being distributed over a large number of secondary
other delivery destinations. It has therefore been found advantageous to
take account of such differences in rates of filling (differences in
volume of mail per destination) and to subdivide the sorting segment of
the postal sorting machine into a first zone having a large number of
sorting outlets for receiving the mailpieces having destinations that
have high rates of filling, and into a second zone having a small number
of sorting outlets for temporarily receiving the mailpieces having
destinations that have low rates of filling.

[0014] The basic idea of the invention is thus to use the space available
in the bins that are partially full of main-destination mailpieces and
that are produced at the end of a first sorting cycle to store
secondary-destination mailpieces during a second sorting cycle, the idea
being that the mailpieces of the secondary destinations that are related
to the main destination of a partially full bin are stored in that bin
after inserting a physical separator therein.

[0015] The term "related" delivery destination is used to mean a
destination for which mail is transported by the same means of transport
as the means used for transporting the mail for the main destination.
Better filling of the bins thus makes it possible to reduce the
proportion of partially full bins and thus to reduce the overall number
of bins that need to be transported.

[0016] The invention thus provides a method of optimizing a process for
handling mail in a sorting machine, said method being characterized in
that it comprises the following steps: subjecting mailpieces to a first
machine-sorting cycle in which a plurality of first sorting outlets of
the sorting machine are allocated to respective ones of a plurality of
first delivery destinations and at least one other sorting outlet of the
sorting machine is allocated to a plurality of second delivery
destinations; directing separators for physically separating mailpieces
through the sorting machine to respective ones of the first sorting
outlets; and re-circulating to the inlet of the sorting machine the
mailpieces coming from said other sorting outlet and subjecting them to a
second sorting cycle in which the plurality of first sorting outlets are
allocated to respective ones of the plurality of second delivery
destinations.

[0017] If the sorting outlets automatically use storage bins that are
interchangeable and removable, e.g. by using an automatic
bin-manipulation system along each side of the row of sorting outlets of
the sorting machine, at the end of the second sorting cycle, the
mailpieces respectively of a main first destination and of a second
destination related to said main destination find themselves sorted into
layers in the same bin by being separated by a separator.

[0018] More particularly, the invention provides a method of optimizing a
mail handling process, wherein mailpieces are collected and sorted in a
first mail handling center so as to be transported in storage bins to M
second mail handling centers in communication with the first mail
handling center, the sorting of the mail in the first center consisting
in separating the mailpieces in a sorting machine having N sorting
outlets, each of which uses at least one storage bin so as to form M
groups of storage bins in which the mailpieces are stored, these M groups
of storage bins being for respective ones of said M second mail handling
centers, and wherein the sorting machine is controlled by one or more
sorting cycles so as to segment each group of storage bins for a second
mail handling center in such a manner as to distinguish between the
mailpieces stored in said bins as a function of a plurality of delivery
destinations associated with said second mail handling center, said
method being characterized in that it comprises the following steps:

[0019] a) preparing the sorting machine for a first sorting cycle for
sorting the mailpieces, the sorting outlets of the sorting machine
comprising a plurality of first sorting outlets and at least one second
sorting outlet distinct from said first sorting outlets, the preparation
consisting in: [0020] a.1 allocating P first sorting outlets to
respective ones of P first delivery destinations associated with a second
mail handling center in question, and doing so for each second mail
handling center with the condition M×P less than N, where P is
greater than or equal to 1, the P first sorting outlets allocated to a
second center being distinct from the P first sorting outlets allocated
to another second mail handling center; and in [0021] a.2 allocating said
second sorting center to M×P second delivery destinations
associated with respective ones of M second mail handling centers;

[0022] b) subjecting the mailpieces to the first sorting cycle in the
sorting machine so as to collect, in at least one storage bin at each
first sorting outlet, mailpieces corresponding to a first delivery
destination associated with a second mail handling center and, at the
second sorting outlet, mailpieces corresponding to the M×P second
delivery destinations;

[0023] c) inputting into the sorting machine M×P separators so as to
place them in respective ones of the M×P storage bins being filled
at respective ones of said first sorting outlets;

[0024] d) preparing the sorting machine for a second sorting cycle for
sorting the mailpieces, the preparation consisting in: [0025] d.1
allocating the M×P first sorting outlets of the sorting machine to
respective ones of the M×P second delivery destinations associated
with the M second mail handling centers; and in [0026] d.2 re-circulating
into the inlet of the sorting machine the mailpieces received in the
second sorting outlet during the first sorting cycle; and

[0027] e) subjecting said re-circulated mailpieces to the second sorting
cycle in the sorting machine so as to collect, in each storage bin being
filled at each first sorting outlet, mailpieces corresponding to a second
delivery destination, these mailpieces that correspond to a second
delivery destination being separated from the mailpieces that correspond
to a first delivery destination by a separator in said storage bin.

[0028] With the method of the invention for optimizing an automatic mail
sorting process, at the end of the sorting process, at the most M×P
partially full bins are produced. If the size of the sorting machine is
such that additional sorting outlets are still available, the
optimization method of the invention may advantageously have the
following feature: [0029] in step a.2), the preparation further
consists in allocating a third sorting outlet to M×P third delivery
destinations associated with respective ones of the M second mail
handling centers; and [0030] in step b), the mailpieces are subjected to
the first sorting cycle so as to collect, at said third sorting outlet,
the mailpieces corresponding to the M×P third delivery
destinations;

[0031] the following steps being implemented subsequently to step e):

[0032] f) inputting into the sorting machine M×P other separators so
as to place them in respective ones of the M×P storage bins being
filled at respective ones of said first sorting outlets;

[0033] g) preparing the sorting machine for a third sorting cycle for
sorting the mailpieces, the preparation consisting in: [0034] g.1
allocating the M×P first sorting outlets of the sorting machine to
respective ones of the M×P third delivery destinations associated
with the M second mail handling centers; and in [0035] g.2 re-circulating
into the inlet of the sorting machine the mailpieces received in the
third sorting outlet during the first sorting cycle; and

[0036] e) subjecting said re-circulated mailpieces to the third sorting
cycle in the sorting machine so as to collect, in each storage bin being
filled at each first sorting outlet, mailpieces corresponding to a third
delivery destination, these mailpieces that correspond to a third
delivery destination being separated from the mailpieces that correspond
to a second delivery destination by a separator in said storage bin.

[0037] It is thus possible to understand that, in this sorting process,
each mailpiece is re-circulated into the machine not more than once,
thereby contributing to reducing the risks of the mail being damaged, in
addition to limiting the costs of using the machine.

[0038] In addition, the sorting segment can be subdivided optimally when
the magnitude P is determined on the basis of the ratio N/M, with the
condition that N-M×P remains greater than 1. In practice, the
magnitude P is determined in an existing machine having a number of
sorting outlets that is predefined. The magnitude P may thus be adjusted
so that the mailpieces are, in principle, re-circulated once only. When
the number of delivery destinations is too large for the number of
sorting outlets available in the sorting machine, the method of the
invention can be adapted to use, over repeated sorting cycles, the second
sorting outlet, for example. However, it is also possible to subdivide
the batch of mailpieces into a plurality of sub-sets, and to implement
the method of the invention on each sub-set of mailpieces.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] An example of an implementation of the optimization method of the
invention is shown by the drawings, and is described below in more
detail. In the drawings:

[0041]FIG. 2 diagrammatically shows a configuration of a postal sorting
cluster having an outward sorting center and a plurality of inward
sorting centers, which outward and inward sorting centers are in mutual
communication with one another;

[0042]FIG. 3 diagrammatically shows an allocation of the sorting outlets
of the machine for a first sorting cycle using the method of the
invention;

[0043]FIG. 4 diagrammatically shows another allocation of the sorting
outlets of the machine for a second sorting cycle using the method of the
invention;

[0044] FIG. 5 diagrammatically shows yet another allocation of the sorting
outlets for a third sorting cycle using the method of the invention; and

[0045]FIG. 6 diagrammatically shows the main steps of the optimization
method of the invention.

DESCRIPTION OF IMPLEMENTATIONS

[0046] The postal sorting machine shown in FIG. 1 is conventional per se.
It includes an inlet with an unstacker magazine 1 into which mailpieces C
are inserted and placed in a stack on edge. The mailpieces C are
unstacked and put into series one behind the other, e.g. with a pitch
(spacing between the leading edges of two consecutive mailpieces) that is
constant in a sorting conveyor 3 along the path of which an automatic
address recognition system 2 is provided for automatically recognizing
postal addresses. Each mailpiece is then directed by the sorting conveyor
3 towards a sorting outlet S1, S2, S3, . . . , S80 as
is well known. In the example, the sorting machine has eighty sorting
outlets that use interchangeable or removable bins in which the
mailpieces are stored flat.

[0047]FIG. 2 shows a postal sorting cluster with twenty-six mail handling
centers referenced CT. It is understood that the method of the invention
is applicable to postal sorting clusters that are smaller or larger.

[0048] In order to simplify the description of the implementation of the
optimization method of the invention, it is assumed below that the center
referenced CTi is an outward sorting center that is in communication
with twenty-five inward other sorting centers (the center CTi also
itself constituting an inward sorting center). In FIG. 2, only three
other inward sorting centers are shown, namely CT1, CT2, and
CT26, for reasons of clarity of the figure.

[0049] For the purposes of illustrating implementation of the method of
the invention, consideration is thus given to outward sorting in the
center CTi with a sorting machine having N=80 sorting outlets. In
order to perform an outward sorting process over M=26 directions
(corresponding to the twenty-six delivery sorting centers of the
cluster), a segmentation pitch P for segmentation of the N sorting
outlets of the machine is defined using the relationship P=integer value
(N/M), i.e. P=3.

[0050] With this segmentation pitch, there remain two reserve outlets in
the postal sorting machine, and, for each direction, it is thus possible
to use three sorting outlets for pre-sorting three delivery destinations
per inward sorting center.

[0051] For the purposes of illustrating implementation of the method of
the invention, it is considered that the number of delivery destinations
in each inward sorting center is a multiple of the segmentation pitch P,
and, in the example shown, it is considered that there are nine delivery
destinations for each direction. The term "delivery destination", should
be understood to mean a group of delivery addresses that can correspond
to one or more delivery rounds.

[0052] Thus, for the postal center CT1, nine destinations A1,
A2, A3, A'1, . . . , A''3 are shown, in which
A1, A2, A3 are main destinations having high filling rates
representing most (e.g. 80%) of the volume of mail, A'1, A'2,
A'3 are destinations related to the destinations A1, A2,
A3 and having lower filling rates representing a smaller volume of
mail (e.g. in the range 10% of the mail to 20% thereof), and the
destinations A''1, A''2, A''3 are destinations related to
the destinations A1, A2, A3 and having even lower filling
rates, representing an even smaller volume of mail (e.g. less than 10%).
The same representation of the delivery destinations is used for CT2
with the destinations B1, B2, . . . , B''3 and for
CT26 with the destinations Z1, Z2, Z''3.

[0053] The basic idea of the invention is thus to pre-sort, overall,
9×26=234 delivery destinations with a sorting machine having 80
sorting outlets, while limiting the number of sorting cycles and also
while optimizing the level of filling of the sorting outlet bins so as to
limit the presence of partially filled bins at the end of the outward
sorting process.

[0054] FIGS. 3 to 5 together with FIG. 6 illustrate the main steps of the
method of the invention.

[0055] In accordance with the invention, the outward sorting process
starts with a step 10 (in FIG. 6) of parameterizing the sorting machine
so as to prepare a first sorting cycle. In this step 10, other sorting
cycles subsequent to the first sorting cycle can also be prepared.

[0056] In step 6, and as shown in FIG. 3, for the first sorting cycle, the
sorting outlets S1, S2, S3 are allocated to respective
ones of the delivery destinations A1, A2, A3. The sorting
outlets S4, S5, S6 are allocated to respective ones of the
delivery destinations B1, B2, B3, etc. up to the sorting
outlets S76, S77, S78 allocated to the delivery
destinations Z1, Z2, Z3.

[0057] Overall, the step 10 thus consists in allocating P (where P is
greater than 1) successive sorting outlets (in the example, P is equal to
3) to the first P delivery destinations of each direction representing
the largest volume of mail, the P sorting outlets allocated to one
direction naturally being distinct from the P sorting outlets allocated
to another direction, as is visible in FIG. 3.

[0058] In addition, the reserve sorting outlet S79 is allocated to
the next P delivery destinations (in the order corresponding to a
decreasing volume of mail) for all of the directions, i.e., in this
example, to A'1, A'2, A'3, B'1, B'2, B'3, .
. . , Z'3.

[0059] In addition, the reserve outlet S80 is allocated to the next P
delivery destinations (in this order corresponding to a decreasing volume
of mail) for all of the directions, i.e., in this example, to A''1,
A''2, A''3, . . . , Z''3.

[0060] Therefore, the above allocation of the sorting outlets in the first
sorting cycle results in the flow of mail being separated over a large
first sorting zone (S1 to S78) that receives most of the mail
(e.g. 80% of the total volume of mail to be separated), over a small
sorting zone (S79) that receives a much smaller percentage of the
mail (e.g. approximately in the range 10% of the volume to 20% thereof)
and over a third sorting zone (S80) that receives the remainder of
the mail, i.e. less than 10% of the volume. Naturally, the proportions
80%, 20%, and 10% are given by way of example that is not limiting on the
invention.

[0061] The outward sorting process continues in a sorting step 11 in which
the mailpieces are subjected to the first sorting cycle in the machine,
and said mailpieces are thus sorted and collected in the sorting outlet
bins 4 shown in FIG. 3. The line L in FIG. 3 symbolizes a system for
automatically manipulating full bins and empty bins, which system serves
the sorting outlets as is well known. The bins being filled in the
sorting outlets are disposed on top of the line L while the full bins of
mailpieces, which bins have been extracted from the sorting outlets, are
disposed under the line L. In addition, the bins associated with a
particular sorting outlet are arranged in a column under said sorting
outlet.

[0062] The sorting process continues in step 12 with storage bin
separators 5 being inserted, which separators are placed in a stack at
the inlet 1 of the machine, and then with the sorting machine being
caused to direct each separator 5 into a respective bin 4 that is being
filled and that is present in a sorting outlet of the first sorting
segment, namely S1 to S78 as shown in FIG. 4.

[0063] The sorting process then continues in step 13 with the mailpieces
stored in the bins of the reserve outlet S79 (second zone of the
sorting segment) being re-circulated into the inlet of the machine for a
second sorting cycle performed on these mailpieces.

[0064] Provision may be made for the machine to be parameterized in the
above step 10 as indicated above, for the purposes of allocating the
sorting outlets for the second sorting cycle. Allocating the sorting
outlets in the second sorting cycle consists in allocating the sorting
outlets S1, S2, . . . , S78 (of the main sorting segment)
to the delivery destinations A'1, A'2, A'3, B'1,
B'2, B'3, . . . , Z'2, Z'3, as shown in FIG. 4. Thus,
for each destination, P consecutive sorting outlets of the first sorting
segment are allocated to the P first related destinations of this
direction.

[0065] The mailpieces taken from the outlet S79 and re-circulated
into the inlet of the machine are thus subjected (step 14 in FIG. 6) in
the sorting machine to the second sorting cycle so as to be sorted into
the sorting outlets S1 to S78 as shown in FIG. 4. At the end of
this sorting cycle, new bins 4 full of mailpieces are produced by the
sorting outlets S1 to S78 and bins 4 are being filled in said
sorting outlets.

[0066] The process then continues again with a step 15 of inserting
separators 5 into the inlet of the sorting machine and of causing the
machine to direct each of said separators to a partially full storage bin
at each sorting outlet S1 to S78, as shown in FIG. 5.

[0067] The sorting process then continues in step 16 with the mailpieces
stored in the bins of the reserve outlet S80 (third zone of the
sorting segment) being re-circulated into the inlet of the machine for a
third sorting cycle on these mailpieces. FIG. 5 shows the third sorting
cycle. In this third sorting cycle, the sorting outlets S1 to
S78 are allocated to the delivery destinations A''1, A''2,
A''3, B''1, B''2, . . . , Z''1, Z''2, Z''3.
Thus, P consecutive sorting outlets P are allocated to the P second
related destinations of each direction.

[0068] Finally, in step 17 (FIG. 6), the mailpieces taken from the reserve
outlet S80 and re-circulated into the inlet of the sorting machine
are subjected to the third sorting cycle for sorting them into the
sorting outlets S1 to S78 of the main sorting section.

[0069] At the end of step 17, the outward sorting process is finished. As
can be seen in FIG. 5, for each sorting outlet S1 to S78 of the
main sorting segment, a certain number of bins 4 of mailpieces have been
produced, including a single partially full bin. For each direction such
as CT1, at the most three partially full bins are produced over all
of the bins filled with mailpieces and corresponding to each direction.
In addition, the mailpieces corresponding to the various delivery
destinations such as A1, A'1, A''2 are distinguished
between in the bins by separators 5, thereby making it easy, during the
subsequent inward sorting, to extract the mailpieces from the bins while
maintaining the order of the pre-sorting achieved during the outward
sorting.

[0070] It should be noted that, during the various sorting cycles of the
sorting process, a signage label may be affixed to each bin that includes
a separator serving to separate two layers of mailpieces so that such
separation is easily identifiable by a machine operator during the inward
sorting.

[0071] In a conventional sorting process, the proportion of partially full
bins may be as high as about 25% of all of the bins produced by the
outward sorting. The method of the invention for optimizing the outward
sorting process makes it possible to reduce this proportion to about 9%,
thereby contributing to reducing the costs of transporting the mailpieces
between the various sorting centers of a cluster.

[0072] The segmentation pitch P of the sorting outlets depends, in
principle, on the number of sorting outlets available in the sorting
machine, on the number of delivery destinations to cover, and on the
number of mail handling centers to serve. The segmentation of the sorting
outlets in the above example corresponds to maximum operating efficiency
for a sorting machine having 80 sorting outlets for sorting 234 delivery
destinations distributed over 26 postal sorting centers.